BACKGROUND
[0002] Cellular tower sites are increasingly distributed around the world to provide mobile
communications for a variety of devices. Such sites typically include a radio unit
connected to an antenna using radio frequency (RF) cabling, where the radio unit is
supplied power by an input power cable (e.g., at -48 volts DC) and a return cable
back to a power supply located in a shelter. Additionally, data is communicated between
one or more base station units (also located in the shelter) and the radio unit over
fiber optic cabling.
[0003] The cellular site also performs various processing to, for example, determine the
appropriate frequency band for a transmission, amplify a signal, transmit and receive
signals, etc. In older networks, this type of processing was typically done at the
base inside the shelter, but after the introduction of third-generation (3G) and fourth-generation
(4G) networks, at least some such processing (e.g., analog/digital conversion) has
largely been moved from the base station unit in the shelter to a processing unit
located near the top of the cellular tower, since a considerable amount of energy
would otherwise be lost via the radio frequency (RF) cable connection between the
base station unit and the antenna(s) at the top of the tower.
[0004] However, while performing processing at the top of the tower near the antenna helps
to minimize energy loss, additional power and fiber optic cabling is required to supply
power and data from the shelter to the unit on the tower. Conventional processing
units are thus susceptible to damage and disruption from overvoltage and surge current
when a lightning strike hits the tower (or nearby). Additionally, towers may host
a number of different radio/antenna combinations, thus providing an issue for routing
multiple DC link cables to fit the radios, and protecting the connections from overvoltage.
[0005] In some cases, hybrid cables are used in cellular sites to combine both fiber and
power conductors. Inside such hybrid cables, there are copper wires that feed several
radios with power, along with fiber optic cabling to provide a data connection to
the radios. Typically, the hybrid cable is terminated in an enclosure and individual
surge protectors are provided for each of the DC circuits that feed the radio. The
fibers from the fiber optic cabling are terminated inside the enclosure and fiber
jumpers are used to connect them to the radios. Likewise, power jumpers are used to
connect the power wiring to each radio to the enclosure. An example of a cable breakout
assembly is described in
U.S. Patent No. 9,575,277, the entire disclosure of which is incorporated by reference herein in its entirety.
[0006] One significant issue arising in conventional cellular sites is that the space available
for the fiber optic breakout assembly (and other components) is extremely limited
on the cellular tower, and this space is often costly for cellular operators to rent
from owners of the tower. Embodiments of the present disclosure address this issue
(among others) by providing a hybrid distribution unit that can distribute both power
and data connections from a power and fiber cables (or from a hybrid cable containing
both power and fiber) within a compact enclosure that helps reduce the overall footprint
of the hybrid distribution unit mounted on a cellular tower.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The included drawings are for illustrative purposes and serve to provide examples
of possible structures and operations for the disclosed inventive systems, apparatus,
methods and computer-readable storage media. These drawings in no way limit any changes
in form and detail that may be made by one skilled in the art without departing from
the spirit and scope of the disclosed implementations.
FIG. 1 illustrates an example of a power and communication system in accordance with
various embodiments of the disclosure.
FIGs. 2A, 2B, and 2C illustrate examples of interior views of a hybrid antenna distribution
unit in accordance with some embodiments.
FIGs. 2D, 2E, and 2F are cut-away views of the hybrid antenna distribution unit shown
in FIGs. 2A-2C.
FIGs. 3A and 3B illustrate an example of the exterior portion of a hybrid distribution
unit in accordance with various embodiments of the disclosure.
FIG. 3C illustrates an example of a hybrid adaptor in accordance with various embodiments
of the disclosure.
FIG. 3D illustrates an example of a hybrid cable that may be used to connect to the
adaptor depicted in FIG 3C.
FIG. 3E illustrates a cut-away view of the exterior portion of the hybrid distribution
unit shown in FIGs. 3A and 3B.
FIG. 4 illustrates an example of a process for manufacturing a hybrid distribution
unit in accordance with various embodiments of the disclosure.
DETAILED DESCRIPTION
[0008] The disclosed embodiments relate to methods and systems for a hybrid distribution
unit. The following description is presented to enable one of ordinary skill in the
art to make and use the invention and is provided in the context of a patent application
and its requirements. Various modifications to the exemplary embodiments and the generic
principles and features described herein will be readily apparent. The disclosed embodiments
are mainly described in terms of particular methods and systems provided in particular
implementations. However, the methods and systems will operate effectively in other
implementations. Phrases such as "one embodiment" and "another embodiment" may refer
to the same or different embodiments. The embodiments will be described with respect
to systems and/or devices having certain components. However, the systems and/or devices
may include more or less components than those shown, and variations in the arrangement
and type of the components may be made without departing from the scope of the invention.
The disclosed embodiments will also be described in the context of particular methods
having certain steps. However, the method and system operate effectively for other
methods having different and/or additional steps and steps in different orders that
are not inconsistent with the exemplary embodiments. Thus, the disclosed embodiments
are not intended to be limited to the embodiments shown, but is to be accorded the
widest scope consistent with the principles and features described herein.
[0009] FIG. 1 illustrates one example of a power and communication system 12 that provides
suppression for a distributed wireless communication station. A building 24 contains
computing equipment for a base transceiver communication station (BTS) 46, which may
also be referred to herein as a "baseband unit." Communication station 46 is connected
through fiber optic cables 38 to different radios 18 (also referred to herein as "remote
radio units") located on the top of a tower 14. A Direct Current (DC) power plant
44 is connected through DC power cables 30 to the different radios 18 on tower 14.
The power plant 44 may also be referred to herein as a "power supply unit." In one
example, DC power cables 30 include sets of -48 DC volt power cables 32, return power
cables 34, and associated ground cables. In one example, power cables 30 and fiber
optic cables 38 are run through a same hybrid trunk cable 48 that is routed out of
building 24 and up tower 14 to a hybrid antenna distribution unit 50 of the disclosed
embodiments.
[0010] A local base suppression unit 40 may be located inside of building 24 and connected
to the local ends of power cables 30 relatively close to DC power plant 44 and communication
station 46. In one embodiment, base suppression unit 40 is located in a rack 26 that
also contains DC power plant 44. In another example, base suppression unit 40 is located
in another rack or some other location next to power plant 44. Examples of base suppression
units are described in
U.S. Patent No. 10,181,717 which is incorporated by reference in its entirety.
[0011] Hybrid antenna distribution unit (also referred to herein as a "hybrid distribution
unit") 50 is attached to a support 52 on top of tower 14 and is connected to the remote
ends of power cables 30 and fiber optic cables 38 proximate to radios 18 and antennas
16. In one example, distribution unit 50 is located within 2 meters of radios 18.
Radios 18 may be connected to their respective antennas 16 via short RF cables.
[0012] The hybrid distribution unit may also be referred to herein as a hybrid fiber to
the antenna (FTTA) / power to the antenna (PTTA) distribution unit. As illustrated
in Figure 1, the hybrid distribution unit 50 may be installed on a mobile communications
tower or mast (such as tower 14) to provide for the connection and distribution of
the hybrid trunk cable 48 to the jumpers 54 coupled to the remote radio units 18.
As described in more detail, below, the hybrid distribution unit 50 also provides
integrated over voltage protection (OVP) modules to help protect the remote radio
units 18 (also referred to herein as "RRUs").
[0013] Among other things, hybrid FTTA/PTTA distribution units of the present disclosure
help provide higher installation capacity compared to conventional distribution units,
as the hybrid distribution units of the present disclosure can support a high number
of RRUs in a small footprint. Furthermore, the hybrid distribution units of the present
disclosure help simplify deployment and accelerate installations as they can be provided
pre-terminated (e.g., no cable connections required in the field).
[0014] FIG. 2A illustrates an interior view of a hybrid antenna distribution unit 50 in
accordance with some embodiments. In this example, hybrid distribution unit 50 includes
an enclosure 205 having an interior portion as shown. A cable entry and clamping mechanism
210 is disposed at the bottom of the enclosure 205 and is configured to receive a
hybrid trunk cable 212 that includes one or more sets of power cables and one or more
fiber optic cables. In alternate embodiments, the cable entry and clamping mechanism
may be configured to receive separate power and data cables, such as a first trunk
cable that includes one or more sets of power cables and a second trunk cable that
includes one or more fiber optic cables.
[0015] Among other things, the enclosure 205 allows both the factory and field installation
of the trunk cable(s) to the hybrid distribution unit 50. For example, in some cases
the hybrid distribution unit may be pre-wired and terminated during factory assembly
such that an installer is not required to make any cable connections in the field.
Additionally or alternatively, a user may remove the external dust cover of the hybrid
distribution unit 50 (described in more detail below) to access the internal portion
of the enclosure to add or modify wiring connections.
[0016] The enclosure may be sized and dimensioned to effectively route power and data cabling
while only requiring a minimal footprint on the cellular tower. As shown in Figure
2A, for example, the enclosure is tapered at the bottom such that the width of the
top of the enclosure is wider than the width of the bottom. This helps to conserve
space while still providing an efficient and effective routing of the cabling that
can easily be accessed by installers or maintenance personnel.
[0017] The enclosure 205 may house one or more overvoltage protection (OVP) modules. In
the example shown in Figure 2A, OVP modules 215a, 215b, and 215c are disposed at the
bottom of the interior portion of the enclosure, with OVP module 215a coupled to a
first elongated bus bar 220a extending along a portion of the length of enclosure
205 (along the left side of the enclosure) and a second elongated bus bar 220b extending
along a portion of the length of enclosure 205 parallel to the first bus bar 220a.
In this example, the first bus bar 220a is an input power bus bar (-48V in this example)
and the second bus bar 220b is a return power bus bar. In Figure 2A, a ground plate
222 is disposed in the bottom of the enclosure 205 and is configured to extend and
connect (e.g., through ground wiring) to the OVP modules 215a, 215b, and 215c.
[0018] Figure 2B provides a more detailed view of the power connections within the enclosure
205. In this example, there are three pairs of elongated bus bars (a -48V bar and
corresponding return "RTN" bar) running lengthwise within the enclosure, though in
alternate embodiments there may be more or fewer sets of bus bars.
[0019] As illustrated in Figure 2B, The power conductors of the hybrid (or power) trunk
cable are connected to the terminals of the OVP modules 215a, 215b, and 215c at the
bottom of the housing. To optimize the cable routing and minimize the assembly and
installation time, two bars, -48V and RTN, equipped with lugs are connected to each
OVP module and run lengthwise along the housing. For example, OVP 215a is connected
to bars 220a and 220b.
[0020] As shown in Figure 2A, short factory terminated power cables are used for the connection
of the bars' lugs to the proper terminals of the hybrid (or power) adaptors. For example,
short power cable 225 connects the input power connection from adaptor 230 to the
lug 235 on the first bus bar 220a.
[0021] The fiber optic portion of the hybrid cable (or the fiber optic cable in case of
separate power and fiber optic trunk cables) is routed above the OVP modules through
the interior portion of the enclosure 205. Figure 2C illustrates the enclosure 205
with the addition of fiber optic cable support elements 240 coupled to opposite sides
of the enclosure. The fiber optic cable support elements 240 are configured to retain
one or more fiber optic cables using one or more fasteners. In this example, three
fiber optic cable support elements 240 are depicted running across the width of the
enclosure, but in alternate embodiments more or fewer support elements may be used,
and the elements may run in any suitable configuration (e.g., lengthwise) in the enclosure.
[0022] The fiber optic cable support elements 240 allow portions of the fiber optic cables
245 to be fastened to the support elements 240 using, for example, hook-and-loop fasteners
coupled to the support elements 240. Additionally, the support elements 240 may be
disposed between the fiber optic cabling 245 and the removably attachable dust cover
(discussed below) to help protect the fiber optic cable against crimping or other
damage during the assembly of the housing. Figures 2D, 2E, and 2F are exploded views
of the hybrid antenna distribution unit shown in Figures 2A-2C.
[0023] Figures 3A and 3B illustrate an example of the exterior portion 300 of hybrid distribution
unit 50. In this example, portion 300 may be coupled (e.g., using screws or nuts and
bolts around the perimeter of portion 300) to a dust cover 330 that encloses and protects
the interior portion of the enclosure 205. The dust cover 330 may also include (or
be coupled to) support brackets 335 that allows the hybrid distribution unit 50 to
be mounted on the cellular tower 14. Figure 3E illustrates a cut-away view of the
exterior portion of the hybrid distribution unit shown in Figures 3A and 3B.
[0024] As shown in Figure 3A, the exterior portion 300 includes a plurality of angled tiered
platforms 310, with each platform configured to retain a row of adapters 320. In this
example, four angled platforms are shown, each with three adaptors per platform, but
alternate embodiments may include more or fewer platforms, and more or fewer adaptors
per platform. In this example, the plurality of angled tiered platforms 310 are angled
toward the bottom of the enclosure. Among other things, this assists an installer
(usually standing below the hybrid distribution unit 50 on a ladder or other support)
to connect or disconnect cabling to the adaptors 320.
[0025] Figure 3C illustrates a detailed view of the terminals of a hybrid adaptor 320 that
may be used in conjunction with embodiments of the present disclosure. In alternate
embodiments, hybrid distribution units of the present disclosure may operate in conjunction
with adaptors of any suitable size, shape, and configuration. In the example depicted
in Figure 3C, adaptor 320 includes a pair of power terminals 350, corresponding to
an input power terminal and return power terminal as discussed above. The adaptor
320 further includes fiber optic connectors 360. The power terminals 350 and fiber
optic terminals 360 connect to the power cables and fiber optic cables, respectively,
as shown in the interior view of the hybrid distribution unit 50 in Figure 2A. For
example, power jumper cables (e.g., power jumper cable 225) and fiber optic jumper
cables (e.g., fiber optic jumper cable 226) plug into the ends of power terminals
350 and fiber optic terminals 360, respectively. Figure 3D illustrates an example
of a hybrid cable that may be used to connect to the adaptors 320. In this example,
the hybrid RRU jumper cable includes supply power (-48) and return (RTN) power lines,
along with fiber optic connectors 360. There are two pairs of fiber optic connectors
360 in this example, one pair for the top set of connectors 360 and one for the pair
for the bottom set of connectors 360 shown in Figure 3C.
[0026] Figure 4 illustrates an example of a process for manufacturing a hybrid distribution
unit according to various embodiments. The hybrid distribution units of the present
disclosure provide a number of advantages over conventional systems. For example,
embodiments of the disclosure help provide both overvoltage protection and fiber/power
cabling distribution in a small footprint housing. The mechanical design and the use
of bars in the interior of the housing allow the reduction of the required volume
for the connection of the cables. The hybrid distribution units of the present disclosure
provide space for the safe routing of the fiber optic cables, taking into consideration
the minimum bend radius requirements, while also protecting the fiber cabling from
damage and doing so with a minimal footprint. Additionally, the hybrid distribution
units of this disclosure can either factory terminated or installed in the field,
and can be configured to be compatible with a variety of hybrid trunk cabling or stand-alone
power/fiber cabling.
[0027] The figures listed above illustrate examples of embodiments of the application and
the operation of such examples. In the figures, the size of the boxes is not intended
to represent the size of the various physical components. Where the same element appears
in multiple figures, the same reference numeral is used to denote the element in all
of the figures where it appears.
[0028] While some implementations have been described herein, it should be understood that
they have been presented by way of example only, and not limitation. Thus, the breadth
and scope of the present application should not be limited by any of the implementations
described herein, but should be defined only in accordance with the following and
later-submitted claims and their equivalents.
1. A hybrid distribution unit apparatus comprising:
an enclosure having an interior portion, exterior portion, a bottom, and a length;
a first elongated bus bar extending along at least a portion of the length of the
interior portion of the enclosure and configured to connect to a first set of one
or more power cables entering the interior portion from the bottom of the enclosure;
a second elongated bus bar extending along at least a portion of the length of the
interior of the enclosure and configured to connect to a second set of one or more
power cables entering the interior portion from the bottom of the enclosure; and
a plurality of adapters extending from the exterior portion of the enclosure, each
adapter including a first set of one or more connectors configured to connect one
or more power jumper cables to the first and second elongated bus bars and a second
set of one or more connectors configured to connect one or more fiber optic jumper
cables to the ends of one or more fiber optic cables entering the interior portion
of the enclosure from the bottom of the enclosure.
2. The hybrid distribution unit apparatus of claim 1, wherein the exterior portion of
the enclosure includes a plurality of angled tiered platforms, each of the plurality
of angled tiered platforms configured to retain a row of the adapters, in particular,
wherein the plurality of angled tiered platforms are angled toward the bottom of the
enclosure.
3. The hybrid distribution unit apparatus of claim 1 or 2, further comprising a dust
cover that is removably attachable to the hybrid distribution unit apparatus to enclose
the interior portion of the enclosure.
4. The hybrid distribution unit apparatus of any of the preceding claims, wherein the
enclosure includes a top, and wherein a width of the top of the enclosure is greater
than a width of the bottom of the enclosure.
5. The hybrid distribution unit apparatus of any of the preceding claims, wherein the
first bus bar is an input power bus bar and the second bus bar is a return power bus
bar, more particular wherein the input power bus bar is a -48V bus bar.
6. The hybrid distribution unit apparatus of claim 5, wherein the first set of one or
more connectors for each respective adaptor includes:
a respective first power conductor coupled to a respective first lug on the first
bus bar; and
a respective second power conductor coupled to a respective second lug on the second
bus bar.
7. The hybrid distribution unit apparatus of any of the preceding claims, further comprising
one or more overvoltage protection (OVP) modules disposed within the interior portion
of the enclosure and coupled to one or more of the first bus bar and the second bus
bar, in particular wherein the one or more OVP modules are disposed at the bottom
of the interior of the enclosure.
8. The hybrid distribution unit apparatus of claim 7, further comprising a ground plate
configured to extend and connect to each of the one or more OVP modules.
9. The hybrid distribution unit apparatus of any of the preceding claims, further comprising
one or more fiber optic cable support elements coupled to enclosure and configured
to retain one or more fiber optic cables using one or more fasteners.
10. The hybrid distribution unit apparatus of claim 9, wherein the one or more fasteners
include a hook-and-loop fastener coupled to one of the fiber optic cable support elements.
11. The hybrid distribution unit apparatus of claim 9, wherein the one of the fiber optic
cable support elements are disposed between the one or more retained fiber optic cables
and a dust cover that is removably attachable to the hybrid distribution unit apparatus.
12. The hybrid distribution unit apparatus of any of the preceding claims, further comprising
a cable entry and clamping mechanism disposed at the bottom of the enclosure, in particular
wherein the cable entry and clamping mechanism is configured to receive a hybrid trunk
cable that includes the first set of power cables, the second set of power cables,
and the one or more fiber optic cables,
or
wherein the cable entry and clamping mechanism is configured to receive a first trunk
cable that includes the first set of power cables and the second set of power cables,
and a second trunk cable that includes the one or more fiber optic cables.
13. The hybrid distribution unit apparatus of any of the preceding claims, wherein the
one or more power jumper cables are removably connectable to the bus bars, and the
one or more fiber optic jumper cables are removably connectable to the ends of the
one or more fiber optic cables.
14. A mobile communication tower system comprising:
a tower; and
a hybrid distribution unit apparatus, in particular according to any of the preceding
claims, coupled to the tower and including:
an enclosure having an interior portion, exterior portion, a bottom, and a length;
a first elongated bus bar extending along at least a portion of the length of the
interior of the enclosure and configured to connect to a first set of one or more
power cables entering the interior portion from the bottom of the enclosure from a
power supply unit;
a second elongated bus bar extending along at least a portion of the length of the
interior of the enclosure and configured to connect to a second set of one or more
power cables entering the interior portion from the bottom of the enclosure from the
power supply unit; and
a plurality of adapters extending from the exterior portion of the enclosure, each
adapter including a first set of one or more connectors configured to connect one
or more power jumper cables to the first and second elongated bus bars and a second
set of one or more connectors configured to connect one or more fiber optic jumper
cables to the ends of one or more fiber optic cables entering the interior portion
of the enclosure from the bottom of the enclosure from a baseband unit.
15. A method of manufacturing a hybrid distribution unit apparatus, in particular according
to any of claims 1-13, the method comprising:
providing an enclosure having an interior portion, exterior portion, a bottom, and
a length;
providing a first elongated bus bar extending along at least a portion of the length
of the interior of the enclosure and configured to connect to a first set of one or
more power cables entering the interior portion from the bottom of the enclosure;
providing a second elongated bus bar extending along at least a portion of the length
of the interior of the enclosure and configured to connect to a second set of one
or more power cables entering the interior portion from the bottom of the enclosure;
and
providing a plurality of adapters extending from the exterior portion of the enclosure,
each adapter including a first set of one or more connectors configured to connect
one or more power jumper cables to the first and second elongated bus bars and a second
set of one or more connectors configured to connect one or more fiber optic jumper
cables to the ends of one or more fiber optic cables entering the interior portion
of the enclosure from the bottom of the enclosure.